This invention relates to a process for indicating abnormalities in vehicles driven by internal combustion engines.
Different types of systems are known in which the inducement of irregular engine running is used as an alarm signal to alert the driver that the engine is or soon will be in a critical condition.
In U.S. Pat. No. 4,459,951, for example, a system is shown in which the ignition system is actuated in such a manner that the ignition spark generation is interrupted increasingly as the engine temperature is exceeded, so that the engine gradually decelerates. In U.S. Pat. No. 4,562,801 the ignition system is actuated on the basis of the lubricating oil level, and in U.S. Pat. No. 4,966,115 the ignition system is actuated in such a manner that when an abnormal condition has been detected a specific ignition setting curve is selected.
In U.S. Pat. No. 5,060,608 the ignition system is also actuated in such a manner that induced misfiring is proportional to the degree of the abnormal condition. In U.S. Pat. No. 4,899,706, U.S. Pat. No. 4,124,013 and U.S. Pat. No. 4,960,088 different systems are shown in which the engine is switched off when the fuel level drops below a predetermined level.